Motor starting case studies
A motor starting case study for any given electrical network can be performed by reducing the network to a smaller equivalent network consisting of a source (generator/grid), the starting motor (largest motor), another large running motor, and a lumped load. This MS Excel-based spreadsheet is based on this concept and presents a small model of an electrical network that can be adapted for such motor starting case studies.
This is very helpful especially for quick checks as follows:
- What is the largest motor size that can be started with a given generator rating
- What should be the rating of the generator (or nos of generator operated in parallel) for a given load and largest motor size
- Knowing voltage drop during starting conditions for given motor details and hence deciding the key parameter during design (say max allowable starting current)
- Deciding the cable size/number of runs etc.
The spreadsheet performs an iterative calculation based on pre-start load inputs and starting motor data. The detailed analysis may be performed with the help of available software.
Notes:
- Motor starting analyses are generally performed for the largest motor connected to a switchboard.
- For worst-case results, motor starting analyses are generally performed considering the weakest source.
- Considering the above two facts, any given electrical network, where a starting analysis of a motor is required, can be reduced to a simplified network consisting of a source (generator/s or grid), the starting motor (largest motor), the running motor/s (second largest motor/s or motor of the same rating as the largest motor understudy) and other loads lumped together.
- Modeling
This spreadsheet allows the user to model a given network as follows:- Generator/s: The details of one generator shall be entered. If there is more than one generator of identical rating, these can be modeled simply by entering the number of the generator in parallel.
- Grid: The details of the grid shall be entered
- Transformer/s: The details of one transformer shall be entered. If there is more than one transformer of identical rating, these can be modeled simply by entering the number of the transformer in parallel.
- The spreadsheet considered either the “Generator/s” or the “Grid” supply for the motor starting the analysis. The “source for the motor starting analysis” can be selected via the drop-down menu. The selection automatically simulates switching “ON” or “OFF” the respective source breaker.
- Starting Motor: The details of the largest motor connected to the switchboard shall be entered.
- Running Motor/s: The details of the second largest running motor/s (or motor of rating same as the starting motor) connected to the switchboard shall be entered. This model can also be utilized by the user to check the voltage drop at the terminals of any remote motor/s.
- Lumped Load: The details of the remaining load on the switchboard can be modeled as a lumped load. The % motor can be defined which shall be modeled as constant power load while the remaining % of load shall be modeled as constant impedance load for the calculation.
- Error in data entry of the “voltage” input shall be highlighted if bus voltages are much different from the generator terminal voltage input of transformer voltage ratio inputs.
The excel spreadsheet has 2 sheets as follows:
- Sheet title “Preface” with notes explaining the calculation spreadsheet and the summary about the software and
- Sheet title ” Motor starting calculation” where actual data entry and calculations can be performed
| Software: | Motor Starting Calculation |
| Version: | 1.0 |
| Developer: | Hemant Kashikar |
| Size: | 104 Kb |
| Price: | – |
| Download: | Here 🔗 (Get Premium Membership) | Video Courses | Download Updates |
How can I get a copy of the Motor Start calculator spread sheet please?
Hi I’am interested in this case study. How do I download it?
Thank you very much for your effort.
Please can I get free download?
Best Wishes
interested in formulae
Can I get free download?
i needed calculation chart and course
I find your program very informative and solution to basic designing. Thank you.
Pls share the excel password
I am interested on this motor starting case study.
Good Day Hemant
Thank You for this information.
I am not on your level regarding this, but I am going to try and use this to do calculation for an small open cast mine with about 50 380v motors of different size.
Thank You
Jan
How much the cost of your excel program?
how calculator eaffact transient vacuum circuit large indction motor 1100kw 11kv and how calculator all parmater
This excel is password protected. Can u share the password to open this file
Thanks for your excellent effort.
Please I need copy of this calculation
Best Wishes
Service provider
Dear Sir,
It’s asking password for while opening the file. Please help…
This excel is password protected. Can u share the password to open this file.
Kindly send sample sheets.
Good souces!Thanks!
Thanks; Excellent for VDIP due to large motor starting;
Thanks to you all. I have got a lot of useful materials in power systems area for my students
Professor
Ellithy
Very good arrangements Guys, thank you very much.
dear sir
can u please send me a detail example for the above excel sheet
Its an awesome workout and very useful.
Could not enter value generator voltage 6600 v for solo generator mode
Dear Sirs,
many thanks to share your knowledge
On excel file i can’t change selection from main grid to generator grid (generator ON grid OFF)
Could you please help me
Thanks
Piero Vercellino
THIS IS GOOD EXCEL PROGRAM IN THE CALCULATION OF % VOLTAGE STARTING DIP WHEN A LARGE MOTOR IS TARTED SUDDENLY EVEN WHEN ALREADY THERE’S EXISTING LOADS RUNNING.
Very much informative and I like all spreadsheets
Thanks for uploading.
Regards,
Boomi
The excel spreadsheet downloaded just fine for me… It is very involved and I am looking forward to picking at it to fully understand how to use it. The introduction sheet seems very intuitive! Thanks for sharing!
unable to download the excel sheets
Dear Sir / Ma’am,
First of all thanks for making such beautiful site for electrical world.
Problem:
In Electrical software, download file option it gives following errors while downloading file:
1. By right click option : It saves html page instead of excel or other file.
2. By box.com : We’re sorry, the server encountered an unexpected error.
I hope admin will rectify this problem asap.
Thanking you in anticipation.
With best Regards,
Rakesh Dhedhi
Electrical Engineer
Motor Starting Calculation-Rev1.xls
We’re sorry, the server encountered an unexpected error.
INTERESTING ENGAGEMENT,
LOVING IT
unable to download the excel sheets
keen to know more about articles, software, guides & lectures of EEP tech refs as well…
Not able to download excel sheets…plz help
Please elaborate…
thanks a lot, its very helpfull
This site is really excellent i m very thankfull…it can be change my life electrical engineering….
thank you soo much eep.
I am not able to download the excel sheet
hi guys.. i am fresher to engineering…
i would like to learn how motor starting calculation is done.
please send me some technical articles/books in this regard to y mail id ([email protected])
thanks in advance.
I cannot download either. I did as you advised about clearing the cache. When I click on ‘Download’, I am taken to a preview page called ‘Box’ and states that I need to login to it. I never heard of this and why do I need to login to some other site?
William
i am not able to download the excel sheet….
The worksheet not producing resuts for the below combination (even though this is not praticle)
Transformer for voltage rating 11/0.2kV
All loads with 0.2kV
V2 bus voltage 0.2kV
Please advise how to over come this issue
thanks
I have made a vba macro in MS Excel for Transformer Sizing .I want to upload it in this site. How i do it.
Hi mpsaxena2003, you can upload it here: https://electrical-engineering-portal.com/resources/researches-and-projects-rap
I’ll contact you for some information about this spreadsheet, because it will be published in section Electrical Software.
Thank you very much!
why i cant download.. Motor Starting Calculation…
even i had log in
Logout and clear the cache in your browser and then login again. It should work. There was some works and improvements on EEP, so try to clear your cache.
BR
Back again. —- I am new to this and my first time trying to download. I have tried to access other downloads and, apparently, I cannot download anything because it takes me to another website called ‘Box’ and I need to download again! Do I need to have a ‘Box’ account, also? If so, this should be noted and clarified on the very first download page. I feel stupid for not knowing how to do a simple download that I have signed up for. Please give me simple instructions that actually fit the program.
W.G.